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91.
Man-Young Jung So-Jeong Kim Jong-Geol Kim Heeji Hong Joo-Han Gwak Soo-Je Park Yang-Hoon Kim Sung-Keun Rhee 《Journal of microbiology (Seoul, Korea)》2018,56(5):365-371
Members of the family Clostridiaceae within phylum Firmicutes are ubiquitous in various iron-reducing environments. However, genomic data on iron-reducing bacteria of the family Clostridiaceae, particularly regarding their environmental distribution, are limited. Here, we report the analysis and comparison of the genomic properties of Geosporobacter ferrireducens IRF9, a strict anaerobe that ferments sugars and degrades toluene under iron-reducing conditions, with those of the closely related species, Geosporobacter subterraneus DSM 17957. Putative alkyl succinate synthase-encoding genes were observed in the genome of strain IRF9 instead of the typical benzyl succinate synthase-encoding genes. Canonical genes associated with iron reduction were not observed in either genome. The genomes of strains IRF9 and DMS 17957 harbored genes for acetogenesis, that encode two types of Rnf complexes mediating the translocation of H+ and Na+ ions, respectively. Strain IRF9 harbored two different types of ATPases (Na+-dependent F-type ATPase and H+-dependent V-type ATPase), which enable full exploitation of ion gradients. The versatile energy conservation potential of strain IRF9 promotes its survival in various environmental conditions. 相似文献
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93.
Lipocalin 2 (Lcn2) interferes with iron uptake by Brucella abortus and dampens immunoregulation during infection of RAW 264.7 macrophages 下载免费PDF全文
Huynh Tan Hop Lauren Togonon Arayan Tran Xuan Ngoc Huy Alisha Wehdnesday Bernardo Reyes Eun Jin Baek Wongi Min Hu Jang Lee Man Hee Rhee Kenta Watanabe Hong Hee Chang Suk Kim 《Cellular microbiology》2018,20(3)
Lipocalin 2 (Lcn2) is an important innate immunity component against bacterial pathogens. In this study, we report that Lcn2 is induced by Brucella (B.) abortus infection and significantly contributes to the restriction of intracellular survival of Brucella in macrophages. We found that Lcn2 prevented iron uptake by B. abortus through two distinct mechanisms. First, Lcn2 is secreted to capture bacterial siderophore(s) and abrogate iron import by Brucella. Second, Lcn2 decreases the intracellular iron levels during Brucella infection, which probably deprives the invading Brucella of the iron source needed for growth. Suppression of Lcn2 signalling resulted in a marked induction of anti‐inflammatory cytokine, interleukin 10, which was shown to play a major role in Lcn2‐induced antibrucella immunity. Similarly, interleukin 6 was also found to be increased when Lcn2 signalling is abrogated; however, this induction was thought to be an alternative pathway that rescues the cell from infection when the effective Lnc2 pathway is repressed. Furthermore, Lcn2 deficiency also caused a marked decrease in brucellacidal effectors, such as reactive oxygen species and nitric oxide but not the phagolysosome fusion. Taken together, our results indicate that Lcn2 is required for the efficient restriction of intracellular B. abortus growth that is through limiting iron acquisition and shifting cells to pro‐inflammatory brucellacidal activity in murine macrophages. 相似文献
94.
Concentric photothermal coagulation with basket‐integrated optical device for treatment of tracheal stenosis 下载免费PDF全文
Van N. Tran Hyoung Shin Lee Van G. Truong Yun‐Hee Rhee Hyun Wook Kang 《Journal of biophotonics》2018,11(1)
A basket‐integrated optical device is developed to consistently treat tubular tissue by centering an optical diffuser in the lumen. Four nitinol arms in conjunction with the optical diffusing applicator are deployed to induce homogeneous circumferential light emission and concentric photothermal coagulation on tracheal tissue. A 1470‐nm laser light is employed for the tissue testing at various irradiation conditions and evaluated in terms of thermal gradient and temperature evolution. Preliminary experiments on liver tissue demonstrate the concentric development of the radial thermal coagulation in the tissue (eccentric ratio = ~5.5%). The interstitial tissue temperature increases with the total amount of energy delivery (around 65°C). Ex vivo trachea testing yields up to 16.5% tissue shrinkage due to dehydration as well as uniform ablation of the cilia and goblet cells in a mucosa layer under 7‐W irradiation for 10 s. The proposed optical device may be a feasible therapeutic method to entail the circumferential coagulation in the tubular tissues in a reliable manner. 相似文献
95.
96.
Ji-Ye Rhee Seong-Hee Lee Adya Prasad Singh Gap-Chae Chung Sung-Ju Ahn 《Physiologia plantarum》2007,130(2):177-184
The figleaf gourd ( Cucurbita ficifolia Bouché) root system has the ability to take up water and nutrients at low soil temperatures, and in the present paper, we attempt to reveal some of the molecular mechanisms behind this low-temperature tolerance. Exposure of figleaf gourd root system to low temperature induced accumulation of H2 O2 along the plasma membrane but not in the cytoplasm. H+ -ATPase (EC 3.6.1.35) activity of isolated root plasma membranes and root hydraulic conductivity ( Lpr ) were largely insensitive to externally applied H2 O2 . However, using bromocresol purple, it was shown that the acidification of the medium surrounding the root was strongly inhibited with low temperature- and H2 O2 -treated roots. Addition of catalase (EC 1.11.1.6) to the root medium during low-temperature exposure led to a recovery of H+ -efflux along the root surface and increased Lpr , demonstrating the importance of an H2 O2 detoxification system in the root cells. Additional evidence for an increased Lpr was obtained by the Fenton reaction wherein a warming of the solution increased the activity of the detoxification system. All available evidence suggests that the ability of figleaf gourd root system to maintain a low level of H2 O2 in the cytoplasm and to detoxify reactive oxygen species is related to the maintenance of water transport activity at low temperatures. 相似文献
97.
Ahn JH Shin MS Jun MA Jung SH Kang SK Kim KR Rhee SD Kang NS Kim SY Sohn SK Kim SG Jin MS Lee JO Cheon HG Kim SS 《Bioorganic & medicinal chemistry letters》2007,17(9):2622-2628
Inhibitors of dipeptidyl peptidase IV (DPP-IV) have been shown to be effective treatments for type 2 diabetes. A series of beta-aminoacyl-containing cyclic hydrazine derivatives were synthesized and evaluated as DPP-IV inhibitors. One member of this series, (R)-3-amino-1-(2-benzoyl-1,2-diazepan-1-yl)-4-(2,4,5-trifluorophenyl)butan-1-one (10f), showed potent in vitro activity, good selectivity and in vivo efficacy in mouse models. Also, the binding mode of compound 10f was determined by X-ray crystallography. 相似文献
98.
Jung WS Hong CK Lee S Kim CS Kim SJ Kim SI Rhee S 《The Journal of biological chemistry》2007,282(11):8414-8423
Inulin fructotransferase (IFTase), a member of glycoside hydrolase family 91, catalyzes depolymerization of beta-2,1-fructans inulin by successively removing the terminal difructosaccharide units as cyclic anhydrides via intramolecular fructosyl transfer. The crystal structures of IFTase and its substrate-bound complex reveal that IFTase is a trimeric enzyme, and each monomer folds into a right-handed parallel beta-helix. Despite variation in the number and conformation of its beta-strands, the IFTase beta-helix has a structure that is largely reminiscent of other beta-helix structures but is unprecedented in that trimerization is a prerequisite for catalytic activity, and the active site is located at the monomer-monomer interface. Results from crystallographic studies and site-directed mutagenesis provide a structural basis for the exolytic-type activity of IFTase and a functional resemblance to inverting-type glycosyltransferases. 相似文献
99.
100.
Hong OK Lee SH Rhee M Ko SH Cho JH Choi YH Song KH Son HY Yoon KH 《Journal of cellular biochemistry》2007,101(3):665-675
Pancreatic islet fibrosis observed in Type 2 diabetes is one of the major factors leading to progressive beta-cell loss and dysfunction. Despite its importance, the mechanism of islet-restricted fibrogenesis associated with pancreatic stellate cell (PSC) activation and proliferation remains to be defined. Therefore, we studied whether the islet-specific environment represented by hyperglycemia and hyperinsulinemia had additive effects on the activation and proliferation of cultured rat PSCs. Cells were stimulated to activate and proliferate with glucose and insulin, either individually or concomitantly. Both stimuli promoted PSC proliferation and extracellular signal-regulated kinase (ERK) 1/2 phosphorylation independently, but an additive effect was also demonstrated. Blockade of ERK signaling by the mitogen-activated protein kinase kinase (MEK) inhibitor, U0126, suppressed both glucose- and insulin-induced ERK 1/2 phosphorylation and PSC proliferation. Glucose and insulin-induced ERK 1/2 phosphorylation also stimulated connective tissue growth factor gene expression. Thus, hyperglycemia and hyperinsulinemia are two crucial mitogenic factors that activate and proliferate PSCs, and the presence of both states will amplify this response. 相似文献